Motion detection switch

ABSTRACT

In a preferred form, a compact motion detecting switch mechanism for detecting movement of an automotive vehicle and which is operable to control operation of an electrical device or devices of the vehicle when the latter is moving and/or stopped is provided. The motion detecting switch mechanism comprises a housing means containing a liquid and which has a pumping chamber having an inlet for ingress of fluid and an outlet for egress of fluid, a rotary pump means disposed within the pumping chamber and which is adapted to be drivingly connected with a moving part of the vehicle for pumping liquid under pressure from the inlet toward the outlet, a switch means carried by the housing and which is adapted to be operatively connected with the electrical device or devices, a recirculating passage in the housing means for recirculating the liquid from the outlet toward the inlet of the pumping chamber, and a combined switch actuator and valve means slidably supported by the housing means for respectively controlling actuation and deactuation of the switch means and for controlling communication between the recirculating passage and the inlet of the pumping chamber. The combined switch actuator and valve means and housing of the switch mechanism are constructed and arranged such that the switch is actuated prior to the establishment of communication between the recirculating passage and the inlet of the pumping chamber.

United States Patent [72] Inventors Kenneth R. Skinner Bloomington, 111.; David P. Clayton, Anderson, Ind. [21] Appl. No. 877,701 [22] Filed Nov. 18, 1969 [45] Patented Apr. 6, 1971 [73] Assignee General Motors Corporation Detroit, Mich.

[54] MOTION DETECTION SWITCH 8 Claims, 5 Drawing Figs.

[52] US. Cl ZOO/61.39, 200/8 1 .9 [51] Int. Cl. H0lh 35/40 [50] Field of Search ZOO/81.9, 152.8, 61.46, 56, 61.86, 61.39; 73/261, 523, 524; 180/106 [56] References Cited UNITED STATES PATENTS 1,569,223 7/1922 Gore 180/106 2,427,453 9/1947 Hadley ZOO/61.39

Primary Examiner-Robert K. Schaefer Assistant ExaminerM. Ginsburg Attorneys-W. E. Finken and W. A. Schuetz ABSTRACT: In a preferred form, a compact motion detecting switch mechanism for detecting movement of an automotive vehicle and which is operable to control operation of an electrical device or devices of the vehicle when the latter is moving and/or stopped is provided. The motion detecting switch mechanism comprises a housing means containing a liquid and which has a pumping chamber having an inlet for ingress of fluid and an outlet for egress of fluid, a rotary pump means disposed within the pumping chamber and which is adapted to be drivingly connected with a moving part of the vehicle for pumping liquid under pressure from the inlet toward the outlet, a switch means carried by the housing and which is adapted to be operatively connected with the electrical device or devices, a recirculating passage in the housing means for recirculating the liquid from the outlet toward the inlet of the pumping chamber, and a combined switch actuator and valve means slidably supported by the housing means for respectively controlling actuation and deactuation of the switch means and for controlling communication between the recirculating passage and the inlet of the pumping chamber. The combined switch actuator and valve means and housing of the switch mechanism are constructed and arranged such that the switch is actuated prior to the establishment of communication between the recirculating passage and the inlet of the pumping chamber.

PATENTEU APR sum 3,573,405

INVIL'N'IURS AT TO R NEY MOTION DETECTION SWITCH The present invention relates to a motion detecting switch mechanism, and more particularly to a motion detecting switch mechanism for detecting movement of an automotive vehicle and which is operable to control operation of an electrical device or devices of the vehicle when the latter is moving and/or stopped.

An important object of the present invention is to provide a new and improved motion detecting switch mechanism for use in detecting when a movable device is moving and for actuating and/or deactuating an electrical device or devices when such motion is detected and not detected, and which is of a compact and economical construction, highly sensitive in detecting movement, capable of actuating heavy duty overcenter switches having high current carrying capacities and which is so constructed and arranged that once the overcenter switch is actuated to one of it's positions, it will not oscillate between its positions due to variations in the pump output.

Another object of the present invention is to provide a new and improved compact motion detecting switch mechanism having a housing means containing a liquid and including a pumping chamber having an inlet and an outlet, a pump means disposed within the pumping chamber and which is adapted to be drivinglyconnected with the movable device for pumping liquid under pressure from the inlet toward the outlet of the pumping chamber, a switch means carried by the housing which is adapted to be operatively connected with an electrical device or devices,-a recirculating passage in the housing means for recirculating the liquid from the outlet toward the inlet of the pumping chamber, and a combined switch actuator and valve means slidably supported by the housing means for respectively controlling actuation and deactuation of the switch means and for controlling communication between the recirculating passage and the inlet of the pumping chamber, and wherein the housing means and the combined switch actuator and valve means are so constructed and arranged that actuation and deactuation of the switch means occurs prior to the establishment and disestablishment of communication between the recirculating passage and the inlet of the pumping chamber, respectively.

A further object of the present invention is to provide a new and improved motion detecting switch mechanism, as defined in the next preceding object, and wherein the combined switch actuator and valve means is in the form of a pin having one end in engagement with a spring biased overcenter switch and its other end provided with a plurality of circumferentially spaced radially extending recesses, and wherein the spring biased overcenter switch normally holds the pin in a first position in which the recesses are not in communication with the inlet of the pumping chamber when the pump is not operating and wherein the pump functions to move the pin to actuate the switch prior to the recesses in the pin establishing communication between the recirculating passage and the inlet of the pumping chamber to provide a bypass for the liquid bein pumped.

A still further object of the present invention is to provide a new and improved motion detecting switch mechanism, as defined in the next preceding object, and wherein the pin also has an axially extending through passage therein to communicate the inlet of the pumping chamber with the recirculating passage after the pump has stopped operating so as to enable the spring biased overcenter switch to be deactuated and return the pin towards its first position in which it blocks communication between the recirculating passage and the inlet of the pumping member.

Yet another object of the present invention is to provide a new and improved motion detecting switch mechanism, as defined in the preceding objects, and wherein the switch housing means includes a resilient expansible and contractable plug member to compensate for volumetric variations due to temperature variations in the liquid contained within the housi'ng whereby the housing is completely filled liquid at all times.

The present invention further resides in various novel constructions and arrangement of parts, and further objects, novel characteristics and advantages of the present invention will be apparent to those skilled in the art to which it relates and from the following detailed description of the illustrated embodiment made with reference to the accompanying drawings forming a part of this specification and in which similar reference numerals or characters are employed to designate corresponding parts throughout the several views, and in which:

FIG. I is a fragmentary perspective view of a preferred embodiment of the motion detecting switch mechanism of the present invention;

FIG. 2 is a reduced scale sectional view taken approximately along line 22 of FIG. 1;

FIG. 3 is an enlarged sectional view taken approximately along line 33 of FIG. 2;

FIG. 4 is a fragmentary view similar to that shown in FIG. 3, but showing difierent parts thereof in different positions; and

FIG. 5 is a sectional view taken approximately along line 5-5 of FIG. 3.

The present invention provides a novel motion detecting switch mechanism. ,Although the motion detecting switch mechanism of the present invention could be used wherever it is desired to detect when a movable device is moving and for actuating and/or deactuating an electrical device when such motion is detected and not detected, it is especially susceptible for use in detecting motion of an automotive vehicle and for controlling operation of an electrical device or devices of the vehicle when the latter is moving and/or stopped. For example, the motion detecting switch mechanism could be used in automatic door locking systems for locking the doors of the vehicle when in motion or for energizing different colored tail lights of a vehicle to indicate that the vehicle is in motion or stopped. Although the particular use of the motion detecting switch mechanism does not per se comprise a part of the present invention, it will, for the purposes of illustration, be herein described as being used for detecting motion of an automotive vehicle and for controlling operation of different colored tail lights of a vehicle for indicating when the vehicle is moving and stopped.

As representing a preferred embodiment of the present invention, FIG. 1 of the drawings shows a motion detecting switch mechanism 10. The motion detecting switch mechanism 10 comprises, in general, housing means 12 for containing a liquid and which includes a piping chamber 14 having an inlet 14a for ingress of fluid and an outlet 14b for egress of fluid; a rotary pump means 16 disposed within the pumping chamber and which is adapted to be driven for pumping liquid under pressure from the inlet toward the outlet of the pumping chamber 14; a switch means 20 carried by the housing means which is adapted to control energization and deenergization of different colored tail lights (not shown) of the vehicle, a recirculating passage means 22 within the housing for recirculating the liquid from the outlet 14b to the inlet 14a of the pumping chamber 14; and a combined switch actuator and valve means 25 slidably supported by the housing means 12 for respectively controlling operation of the switch 7 means 20 and for controlling communication between the recirculating passage 22 and the inlet 14a of the pumping chamber 14.

The housing means 12 comprises a main housing portion 30 having a bottom 30a and integral sidewalls 30b, 30c, 30d, 302. The housing means 12 also includes a cover 32 which is suitably secured to the sidewall portions 30b-30e at their ends remote from the bottom 30a and which defines with the main body portion 30 a sealed enclosure filled with a suitable liquid, such as oil.

The housing means 12 also includes a pair of spaced partitions 35 and 36 integral with the bottom 30a and the sidewall portions 30s and 300, respectively. The partition 35 extends normal to the sidewall portion 30s and the partition 36 has a portion 360 which extends normal to the sidewall 30c and an arcuately curved portion 36b which is spaced from the sidewall portions 30c and 30d.

As best shown in FIG. 3, the partitions 35 and 36 define with portions of the sidewalls 30s and 30d the pumping chamber 14 for housing the rotary pump 16. The partition 36 defines with portions of the sidewalls 30d and 30c and another partition 38 the recirculating passage means 22 for recirculating the liquid from the outlet 14b of the pumping chamber 14 to the inlet 14a thereof. The partition 38 is spaced from the portion 36a of the partition 36 and defines with the sidewall 30b a chamber 48 for housing the switch means 20.

The pump means 16 for pumping fluid under pressure from the inlet 14a toward the outlet 14b of the pumping chamber 14 is a rotary gear pump having a drive gear 42 and a driven gear 44. The drive gear 42 is rotatably supported by the housing means 12 and, in the preferred embodiment, is adapted to be suitably drivingly connected with the transmission and speedometer of the automotive vehicle. To this end, the drive gear 42 includes axially extending shaft portions 42a and 42b extending from its opposite sides and which are rotatably received within aligned openings 45 and 46 in the cover 32 and bottom 30a of the housing means 12. The shaft portions 42a and 42b also freely extend through axially extending openings in hubs 47 and 48 formed integral with the cover 32 and bottom 30a of housing 30, respectively. The hubs 47 and 48 are externally and internally threaded so that the switch mechanism can be secured to a suitable support and the speedometer of the vehicle and with the shaft portion 42a adapted to be drivingly connected with the transmission and the shaft portion 42b adapted to be drivingly connected with the speedometer. The drive gear 42 also has an annular recess 42c surrounding the shaft portions 42a and 42b and the shaft portions carry annular lip seals 49 engageable with the cover 32 and bottom 30a for preventing the escape of liquid from the switch housing means 12 along the shaft portions 42a and 42b.

The driven gear 44 has a central through opening 50 and the bottom 30a and the cover 32 of the housing means 12 are fonned so as to provide aligned inwardly extending stub shaft portions 51 and 52 which are received within the opening 50 to rotatably support the driven gear 44.

When the vehicle is in forward motion, the drive and driven gears 42 and 44 are rotated in the direction of the arrows indicated in FIG. 3 and their intermeshing teeth cause the liquid to be pumped from the inlet 14a under pressure around the peripheries of the gears toward the outlet 14b. The pressurized liquid from the outlet 14b flows through the recirculating passage 22 and engages the combined switch actuator and valve means 25.

The combined switch actuator and valve 25, in the illustrated embodiment, is in the form of a cylindrical pin which is slidably supported by the partitions 36 and 38. To this end, the partition 38 has an opening 55 which is aligned with a semicircular opening 56 in the portion 36a of the partition 36. The cover 32 has an inwardly extending partition (not shown) provided with a semicircular shaped opening which seats against the partition portion 36a to define a circular opening which is aligned with the opening 55 in the partition 38. The pin 25 is slidably received within the openings 55 and 56. The pin 25 has a rounded end 25a which engages the switch means and along its opposite end portion b has a plurality of circumferentially spaced, radially extending fins 60. The circumferentially spaced, radially extending fins 60 define circumferentially spaced, radially extending recesses 62 therebetween.

The pin 25 is movable from a first position, as shown in FIG. 3, in which the pin 25 is disposed relative to the partition portion 36a such that communication between the outlet 14b and the inlet 14a of the pumping chamber 14 via the recirculating passage 22 is blocked, and a second position, as shown in FIG. 4, wherein the pin 25 is disposed relative to the partition portion 36a such that the radially extending recesses 62 thereof place the recirculating passage 22 and the inlet 14a of the pumping chamber 14 in communication with each other.

The pin 25 is normally biased towards its first position, as shown in FIG. 3, when the pump is not operating by the switch means 20. The switch means 20 comprises three spaced, L- shaped, stationary terminals 70, 71 and 72 respectively secured to the bottom 30a of the housing means 12 and to ex ternal spade connectors 73, 74 and by rivets 76. The external connector 73 is adapted to be connected with a suitable power source, such as the battery of the vehicle, and the external spade connectors 74 and 75 are adapted to be respectively connected in circuit with different colored tail lights of the vehicle. The terminal 70 also clampingly secures one end of an overcenter, snap acting leaf spring to the wall 30b of the housing. The overcenter leaf spring 80 is supported in cantilever fashion and at its opposite or free end 82 engages the rounded end 25a of the pin 25.

The snap acting, overcenter spring 80 comprises a onepiece metallic member having a pair of laterally spaced arms 84 integral with the ends and a bowed leaf portion 85 integral with the end portions and located intermediate the arms 84. The arms 84 are crimped, as indicated at 86, so as to cause the intermediate leaf portion to be bowed, as shown in FIG. 3.

The cantilever, overcenter spring 80 is inherently or selfbiased toward the position shown in FIG. 3, when no externally imposed forces are acting thereon. In this position, the intermediate bowed leaf portion 85 is located on the downward side of a plane containing the arms 84 and is in engagement with the stationary terminal 71 to provide a conductive path between the terminals 70 and 71. The overcenter spring 80 biases the pin 25 toward the position shown in FIG. 3 and is in this position when the pump 16 is not operating.

When the pump 16 is rotated to cause fluid under pressure to be pumped through the recirculating passage 22, the pressurized liquid will cause the pin 25 to be moved downwardly from its first position, asshown in FIG. 3, towards its second position, as shown in FIG. 4. As the pin 25 is moved downwardly it causes the arms 84 of the spring 80 to move downwardly relative to the intermediate bowed leaf portion 85, which in turn causes the leaf 85 to tend to be bowed in the opposite direction. When the arms 84 move overcenter with respect to the bowed leaf portion 85, i.e., when the plane containing the arms 84 begins to be disposed beneath the bowed leaf portion 85, the bowed leaf portion 85 will be moved with a snap action from its position shown in FIG. 3 to the position shown in FIG. 4. This breaks the conductive path between terminals 70 and 71 and provides a conductive path between terminals 70 and 72 and thus, deenergizes a first set of colored tail lights and energizes a second set of different colored tail lights.

The pin 25 as the pump 16 continues to operate moves further downward towards its position shown in FIG. 4 until the recesses 62 communicate the recirculating passage 22 with the inlet 14a of the pumping chamber 14 to cause the output of the pump to be recirculated back toward the inlet 14a of the pumping chamber 14.

An important feature of the present invention resides in the fact that the pin means 25 causes the leaf portion 8510 be moved overcenter to disengage the terminal 71 and to engage the terminal 72 prior to the time that the pin 25 is moved far enough to communicate the recesses 62 therein with the inlet 14a of the pumping chamber 14. This insures that the switch means 20 is actuated prior to any recirculation of the pressurized fluid taking place. This also prevents oscillation of the overcenter spring 80 between the terminals 71 and 72 due to variations in the output of the pump.

When the vehicle is stopped the pump 16 stops rotating and the inherent bias of the arms 82 of the spring 80 will return the pin 25 from its position shown in FIG. 4 towards its first position, as shown in FIG. 3. As the spring 80 returns toward its position shown in FIG. 3, the bowed leaf portion 85 will move overcenter with a snap action to disengage the terminal 72 to deenergize the second set of tail lights and to engage the terminal 71 to energize the first set of tail lights. To enable the pressure in the recirculating passage 22 to be equalized to that in chamber 40 and to enable liquid to be displaced from passage 22 the pin means 25 is provided with a relatively small central through aperture 90 which slowly allows fluid to flow from the passage 22 to the chamber 40. This allows the spring 80 to return the pin 25 back towards its first position, as shown in FIG. 3.

The through aperture 90 in the pin 25 also allows fluid to flow from chamber 40 to the recirculating passage 22 when the pump 16 is driven in the reverse direction during backward movement of the vehicle. Also, a suitable one-way check valve operatively associated with the pin 25 or disposed in the partition portion 360 could be provided for recirculating fluid from the chamber 40 to the recirculating passage 22 during backward movement of the vehicle when the pump is driven the reverse direction.

To compensate for variations in the volume of the fluid due to temperature variations, a resilient expandable and compressible plug 95 is provided. The plug is carried by the cover 32 and extends within the chamber 40 of the switch housing means 12. If the volume of the liquid should expand the nose portion 95a of the plug will be compressed and if the volume should become less, the plug will reexpand to fill the void whereby the entire enclosed housing 12 is filled with liquid.

From the foregoing, it should be apparent that a compact and economical motion detecting switch mechanism has been provided. The switch mechanism provides a very reliable switching action and, except for the spring 80 and switch terminals, can be made from a plastic material.

Although the illustrated embodiment thereof has been described in great detail, it should be apparent that certain modifications, changes, and adaptations may be made in the illustrated embodiment, and that it is intended to cover all such modifications, changes and adaptations which come within the spirit of the present invention.

We claim:

1. A compact motion detecting switch mechanism for use in detecting when a movable device is moving and for actuating an electrical device when such motion is detected comprising: a housing meanscontaining a liquid and including a pumping chamber having an inlet for ingress of liquid and an outlet for egress of liquid; a pump means disposed within said pumping chamber and which is adapted to be drivingly connected with the movable device for pumping liquid under pressure from the inlet toward the outlet of the pumping chamber; switch means carried by said housing means and adapted to be operatively connected in a circuit with the electrical device, said switch means including a switch member movable between first and second positions for energizing and deenergizing the electrical device; said switch member being spring biased toward one of said positions, a recirculating passage in said housing means for recirculating the liquid from said outlet toward said inlet of said pumping chamber; and a combined switch actuator and valve means slidably supported by said housing means for respectively controlling movement of said switch member between its positions and for controlling communication between said recirculating passage and said inlet of said pumping chamber, said switch actuator and valve means being engageable with said switch member and provided with a recess, said switch actuator and valve means being spring biased toward a first position in which said recess of the switch actuator and valve means does not communicate the recirculating passage with the inlet of the pumping chamber and in which the switch member is in said one position when the pump means is not operating, and said combined switch actuator and valve means being movable from said first position toward a second position in which its recess communicates the recirculating passage with the inlet of the pumping chamber and in which it holds said switch member in its other position in response to liquid under pressure being pumped by said pump means.

2. A motion detecting switch mechanism as defined in claim 1 wherein said switch member is a snap-acting, overcenter spring and wherein said combined switch actuator and valve means comprise a pin having a plurality of circumferentially spaced, radially extending recesses at one end thereof.

3. A motion detecting switch mechanism as defined in claim 1 wherein said combined switch actuator and valve means comprises a slidable member having said recess and an opening therethrough which allows liquid to slowly flow from the recirculating passage to a chamber in communication with the inlet of the pumping chamber when pump operation is stopped to allow the switch actuator and valve means to be returned toward said first position.

4. A motion detecting switch mechanism as defined in claim 1 wherein said housing means carries a resilient plug extending interiorly thereof and with said plug being expandable and contractable in response to variations in the volume of liquid contained in the housing means due to temperature variations of the liquid.

5. A compact motion detecting switch mechanism for use in detecting when an automotive vehicle is moving and for actuating an electrical device when such motion is detected comprising: a housing means containing a liquid including a pumping chamber having an inlet for ingress of liquid and an outlet for egress of liquid; a pump means disposed within said pumping chamber and which is adapted to be drivingly connected with a part on the vehicle which rotates when the latter is moving and which pumps liquid under pressure from the inlet toward the outlet of the pumping chamber; switch means carried by said housing means and including a pair of spaced stationary terminals and a snap-acting overcenter spring means secured to one of said terminals, said snap-acting overcenter spring means being self-biased toward a first position in which a mobile snap-acting portion thereof is disengaged from the other terminal and a second position upon deflecting its end remote from the end which is secured to the one terminal in which its snap acting portion engages the other terminal to provide a conductive path between the terminals; a recirculating passage in said housing means for recirculating the liquid from said outlet toward said inlet of said pumping chamber; and a combined switch actuator and valve means for actuating the overcenter spring means of the switch means between its positions and for controlling communication between the recirculating passage and the inlet of the pumping chamber, said actuator and valve means having one end engageable with the remote end of the overcenter spring means and having a plurality of radially extending recesses adjacent its other end thereof; said overcenter spring means biasing said actuator and valve means toward a first position in which the recesses are not in communication with the inlet of the pumping chamber to thereby substantially block communication between the recirculating passage and the inlet of the pumping chamber, said combined switch actuator and value means effecting movement of said overcenter spring means to its second position to provide a conductive path between the stationary terminals and communicating the recirculating passage and the inlet of the pumping chamber through its recesses in response to liquid under pressure flowing through said recirculating passage when the pump means is operating when the vehicle is moving, said combined switch actuator and valve means actuating said overcenter spring means to its second position prior to establishing communication between said recirculating passage and the inlet of said pumping chamber.

6. A motion detecting switch mechanism as defined in claim 5 wherein said combined switch actuator and valve means comprises a slidable member having said recesses and an opening therethrough which allows liquid to slowly flow from the recirculating passage to a chamber in communication with the inlet of the pumping chamber when pump operation is stopped to allow the switch actuator and valve means to be returned toward said first position, and wherein said housing means carries a resilient plug extending interiorly thereof and with said plug being expandable and contractable in response to variations in the volume of liquid contained in the housing means due to temperature variations of the liquid.

7. A compact motion detection switch mechanism for use in detecting when an automotive vehicle is moving and for actuating first and second colored tail lights on the vehicle when the vehicle is in motion and stopped comprising: a housing means containing a liquid including a pumping chamber having an inlet for ingress of liquid and an outlet for egress of liquid; a rotary pump disposed within said pumping chamber and which is adapted to be drivingly connected with a part of the vehicle which rotates when the vehicle is in motion and which pumps liquid under pressure from the inlet toward the outlet of the pumping chamber; switch means carried by said housing means and including first, second and third spaced stationary terminals and a snap acting overcenter spring means having one end secured to said first terminal, said snap acting overcenter spring means being self-biased toward a first position in which a mobile snap acting portion thereof is disengaged from the third terminal and in engagement with said second tenninal to energize said first tail lights, said overcenter spring means being movable to a second position upon deflecting its end remote from the end which is secured to said first terminal in which its snap acting portion disengages said second terminal and engages the third terminal to effect deenergization and energization of said first and second tail lights respectively, a recirculating passage in said housing means for recirculating the liquid from said outlet toward said inlet of said pumping chamber; and a pin member for actuating the overcenter spring means of the switch means between its positions and for controlling communication between the recirculating passage and the inlet of the pumping chamber,

said pin member having one end engageable with the other end of the overcenter spring means and having a plurality of circumferentially spaced radially extending recesses adjacent its other end thereof; said overcenter spring means biasing said pin member toward a first position in which the recesses are not in communication with the inlet of the pumping chamber to thereby substantially block communication between the recirculating passage and the inlet of the pumping chamber, said pin member effecting movement of said overcenter spring means to its second position and communicating the recirculating passage and the inlet of the pumping chamber through its recesses in response to liquid under pressure flowing through said recirculating passage when the pump is operating, said pin member actuating said overcenter spring means to its second position prior to establishing communication between said recirculating passage and the inlet of said pumping chamber.

8. A motion detecting switch mechanism as defined in claim 7 wherein said combined switch actuator and valve means comprises a slidable member having said recesses and an opening therethrough which allows liquid to slowly flow from the recirculating passage to a chamber in communication with the inlet of the pumping chamber when pump operation is stopped to allow the switch actuator and valve means to be returned toward said one position. 

1. A compact motion detecting switch mechanism for use in detecting when a movable device is moving and for actuating an electrical device when such motion is detected comprising: a housing means containing a liquid and including a pumping chamber having an inlet for ingress of liquid and an outlet for egress of liquid; a pump means disposed within said pumping chamber and which is adapted to be drivingly connected with the movable device for pumping liquid under pressure from the inlet toward the outlet of the pumping chamber; switch means carried by said housing means and adapted to be operatively connected in a circuit with the electrical device, said switch means including a switch member movable between first and second positions for energizing and deenergizing the electrical device; said switch member being spring biased toward one of said positions, a recirculating passage in said housing means for recirculating the liquid from said outlet toward said inlet of said pumping chamber; and a combined switch actuator and valve means slidably supported by said housing means for respectively controlling movement of said switch member between its positions and for controlling communication between said recirculating passage and said inlet of said pumping chamber, said switch actuator and valve means being engageable with said switch member and provided with a recess, said switch actuator and valve means being spring biased toward a first position in which said recess of the switch actuator and valve means does not communicate the recirculating passage with the inlet of the pumping chamber and in which the switch member is in said one position when the pump means is not operating, and said combined switch actuator and valve means being movable from said first position toward a second position in which its recess communicates the recirculating passage with the inlet of the pumping chamber and in which it holds said switch member in its other position in response to liquid under pressure being pumped by said pump means.
 2. A motion detecting switch mechanism as defined in claim 1 wherein said switch member is a snap-acting, overcenter spring and wherein said combined switch actuator and valve means comprise a pin having a plurality of circumferentially spaced, radially extending recesses at one end thereof.
 3. A motion detecting switch mechanism as defined in claim 1 wherein said combined switch actuator and valve means comprises a slidable member having said recess and an opening therethrough which allows liquid to slowly flow from the recirculating passage to a chamber in communication with the inlet of the pumping chamber when pump operation is stopped to allow the switch actuator and valve means to be returned toward said first position.
 4. A motion detecting switch mechanism as defined in claim 1 wherein said housing means carries a resilient plug extending interiorly thereof and with said plug being expandable and contractable in response to variations in the volume of liquid contained in the housing means due to temperature variations of the liquid.
 5. A compact motion detecting switch mechanism for use in detecting when an automotive vehicle is moving and for actuating an electrical device when such motion is detected comprising: a housing means containing a liquid including a pumping chamber having an inlet for ingress of liquid and an outlet for egress of liquid; a pump means disposed within said pumping chamber and which is adapted to be drivingly connected with a part on the vehicle which rotates when the latter is moving and which pumps liquid under pressure from the inlet toward the outlet of the pumping chamber; switch means carried by said housing means and including a pair of spaced stationary terminals and a snap-acting overcenter spring means secured to one of said terminals, said snap-acting overcenter spring means being self-biased toward a first position in which a mobile snap-acting portion thereof is disengaged from the other terminal and a second position upon deflecting its end remote from the end which is secured to the one terminal in which its snap acting portion engages the other terminal to provide a conductive path between the terminals; a recirculating passage in said housing means for recirculating the liquid from said outlet toward said inlet of said pumping chamber; and a combined switch actuator and valve means for actuating the overcenter spring means of the switch means between its positions and for controlling communication between the recirculating passage and the inlet of the pumping chamber, said actuator and valve means having one end engageable with the remote end of the overcenter spring means and having a plurality of radially extending recesses adjacent its other end thereof; said overcenter spring means biasing said actuator and valve means toward a first position in which the recesses are not in communication with the inlet of the pumping chamber to thereby substantially block communication between the recirculating passage and the inlet of the pumping chamber, said combined switch actuator and value means effecting movement of said overcenter spring means to its second position to provide a conductive path between the stationary terminals and communicating the recirculating passage and the inlet of the pumping chamber through its recesses in response to liquid under pressure flowing through said recirculating passage when the pump means is operating when the vehicle is moving, said combined switch actuator and valve means actuating said overcenter spring means to its second position prior to establishing communication between said recirculating passage and the inlet of said pumping chamber.
 6. A motion detecting switch mechanism as defined in claim 5 wherein said combined switch actuator and valve means comprises a slidable member having said recesses and an opening therethrough which allows liquid to slowly flow from the recirculating passage to a chamber in communication with the inlet of the pumping chamber when pump operation is stopped to allow the switch actuator and valve means to be returned toward said first position, and wherein said housing means carries a resilient plug extending interiorly thereof and with said plug being expandable and contractable in response to variations in the volume of liquid contained in the housing means due to temperature variations of the liquid.
 7. A compact motion detection switch mechanism for use in detecting when an automotive vehicle is moving and for actuating first and second colored tail lights on the vehicle when the vehicle is in motion and stopped comprising: a housing means containing a liquid including a pumping chamber having an inlet for ingress of liquid and an outlet for egress of liquid; a rotary pump disposed within said pumping chamber and which is adapted to be drivingly connected with a part of the vehicle which rotates when the vehicle is in motion and which pumps liquid under pressure from the inlet toward tHe outlet of the pumping chamber; switch means carried by said housing means and including first, second and third spaced stationary terminals and a snap acting overcenter spring means having one end secured to said first terminal, said snap acting overcenter spring means being self-biased toward a first position in which a mobile snap acting portion thereof is disengaged from the third terminal and in engagement with said second terminal to energize said first tail lights, said overcenter spring means being movable to a second position upon deflecting its end remote from the end which is secured to said first terminal in which its snap acting portion disengages said second terminal and engages the third terminal to effect deenergization and energization of said first and second tail lights respectively, a recirculating passage in said housing means for recirculating the liquid from said outlet toward said inlet of said pumping chamber; and a pin member for actuating the overcenter spring means of the switch means between its positions and for controlling communication between the recirculating passage and the inlet of the pumping chamber, said pin member having one end engageable with the other end of the overcenter spring means and having a plurality of circumferentially spaced radially extending recesses adjacent its other end thereof; said overcenter spring means biasing said pin member toward a first position in which the recesses are not in communication with the inlet of the pumping chamber to thereby substantially block communication between the recirculating passage and the inlet of the pumping chamber, said pin member effecting movement of said overcenter spring means to its second position and communicating the recirculating passage and the inlet of the pumping chamber through its recesses in response to liquid under pressure flowing through said recirculating passage when the pump is operating, said pin member actuating said overcenter spring means to its second position prior to establishing communication between said recirculating passage and the inlet of said pumping chamber.
 8. A motion detecting switch mechanism as defined in claim 7 wherein said combined switch actuator and valve means comprises a slidable member having said recesses and an opening therethrough which allows liquid to slowly flow from the recirculating passage to a chamber in communication with the inlet of the pumping chamber when pump operation is stopped to allow the switch actuator and valve means to be returned toward said one position. 